2012 Annual Report
1a.Objectives (from AD-416):
This research will improve our knowledge-base regarding contributions that different vegetation plant communities play in producing surface runoff and soil erosion rates in rangeland watersheds. We hypotheses that alternative stable vegetative states (i.e., cheatgrass dominated sites) will have different hydrologic responses (i.e., infiltration rates, peak discharge rates, and sediment loads) than historical Wyoming sagebrush plant communities. We further hypotheses that sites that have been revegetated will be intermediate in hydrologic response to the historical and disturbed site conditions.
1b.Approach (from AD-416):
The majority of the state of Nevada is rural and limited hydrologic studies have been carried out to investigate surface water hydrology in remote upland regions of the state. For rainfall, there is a limited network of meteorological stations for which data are available through the National Weather Service. Thus the measurement of surface water contributions in small rangeland catchments with intermittent surface runoff is very limited. We propose to investigate the feasibility of instrumenting existing wildlife guzzlers in Nevada to provide data on precipitation and surface runoff in remote catchments. By using a simple water balance approach with appropriate monitoring equipment for precipitation and water levels in the guzzler storage tanks, the amount of surface runoff generated by a particular natural storm can be determined. The second phase will be to estimate the hydrologic response of the different vegetative states within these catchments with a rainfall simulator (2 m wide x 6 m long) at rates 5, 10, 12.5, 15, 17.5 cm per hour. This will provide the baseline data for the watershed analysis of hydrologic response of specific vegetative states at the hillslope scale. Data from these experiments will be used to validate and improve the Rangeland Hydrology Erosion Model and the Soil Water Assessment Tool and will provide benchmark information for the USDA Conservation Effects Assessment Project.
This research directly supports Objective 2: Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands. Specifically Sub-objective 2.1: Develop an integrated package of ground-based and remote sensing tools to quantify and assess the environmental impact of management decisions and conservation practices at hillslope and landscape scales in woodland, shrub-steppe, and desert ecosystems of the Great Basin.
In the arid western United States, wildlife water developments, or “guzzlers,” are important water sources for wildlife, and consist of impermeable roof structures designed to intercept precipitation and small tanks for storing water. Guzzlers are typically installed in remote, mid- to high-elevation basins where precipitation data are often scarce. In this study, small game guzzlers were examined as potential sites for improving estimates of climatic parameters in remote Nevada catchments. Instruments measuring precipitation and water level were installed at two guzzler field sites. Although one field site was vandalized during the study, field results indicated that water levels in the tank measured by Hobo pressure transducers corresponded well with precipitation events measured by the Texas Electronics tipping bucket rain gauge and measured data were similar to PRISM estimates. With over 1600 guzzlers in Nevada and thousands more throughout the western United States, this study’s results demonstrate that guzzler sites can be augmented with climatic instrumentation at a relatively low cost to improve the quality and density of climate observations, benefitting hydrologists, climatologists and wildlife managers.